In a device such as a digital camera, an image imaged by an image sensor is converted into compression data and is supplied through an interface to image processing LSI included in a digital signal processor (DSP) or the like.
Incidentally, as a compression data method in which transmission is performed between an interface of the image sensor and that of the image processing LSI, for example, a method which is a combination of a differential pulse code modulation (DPCM) and a pulse code modulation (PCM) is employed. For example, with respect to an interface between chips for a mobile phone, a standard mobile imaging architecture (SMIA) standard is provided as a standard for compression data (see Non-Patent Document 1).
Also, a method to compress an N bit signal into an n bit signal, to perform decomposition and connection thereof, and to perform an output as N bits is proposed (see Patent Document 1). A purpose is to shorten a pixel data output period by adjusting a data rate, which is reduced into n bits, to a data rate of N bits. That is, for example, 12-bit pixel data is compressed into eight bits and a next pixel is decomposed into four bits. Then, transmission as 12-bit data is performed.